关于pandoc：无法编译Haskell程序(“无法匹配”错误)

Unable to compile Haskell program (“Couldn't match” errors)

我试图在此处实施John MacFarlane的Haskell解决方案，这应该允许我在保留数学运算的同时将具有MathJax(latex)输入的HTML文件转换为.tex。脚本是：

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import Text.Pandoc

main = toJsonFilter fixmath

fixmath :: Block -> Block
fixmath = bottomUp fixmathBlock . bottomUp fixmathInline

fixmathInline :: Inline -> Inline
fixmathInline (RawInline"html" ('<':'!':'-':'-':'M':'A':'T':'H':xs)) =
RawInline"tex" $ take (length xs - 3) xs
fixmathInline x = x

fixmathBlock :: Block -> Block
fixmathBlock (RawBlock"html" ('<':'!':'-':'-':'M':'A':'T':'H':xs)) =
RawBlock"tex" $ take (length xs - 3) xs
fixmathBlock x = x

我安装了Haskell的64位OSX版本，还给出了命令cabal install pandoc以获取pandoc函数。但是，执行后

1	ghc --make fixmath.hs

我收到以下错误：

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[1 of 1] Compiling Main ( fixmath.hs, fixmath.o )

fixmath.hs:9:26:
Couldn't match expected type `Format' with actual type `[Char]'
In the pattern:"html"
In the pattern:
RawInline"html"
('<' : '!' : '-' : '-' : 'M' : 'A' : 'T' : 'H' : xs)
In an equation for `fixmathInline':
fixmathInline
(RawInline"html"
('<' : '!' : '-' : '-' : 'M' : 'A' : 'T' : 'H' : xs))
= RawInline"tex" $ take (length xs - 3) xs

fixmath.hs:10:13:
Couldn't match expected type `Format' with actual type `[Char]'
In the first argument of `RawInline', namely `"tex"'
In the expression: RawInline"tex"
In the expression: RawInline"tex" $ take (length xs - 3) xs

fixmath.hs:14:24:
Couldn't match expected type `Format' with actual type `[Char]'
In the pattern:"html"
In the pattern:
RawBlock"html"
('<' : '!' : '-' : '-' : 'M' : 'A' : 'T' : 'H' : xs)
In an equation for `fixmathBlock':
fixmathBlock
(RawBlock"html"
('<' : '!' : '-' : '-' : 'M' : 'A' : 'T' : 'H' : xs))
= RawBlock"tex" $ take (length xs - 3) xs

fixmath.hs:15:12:
Couldn't match expected type `Format' with actual type `[Char]'
In the first argument of `RawBlock', namely `"tex"'
In the expression: RawBlock"tex"
In the expression: RawBlock"tex" $ take (length xs - 3) xs

出了什么问题我该怎么办？

pandoc的最新版本更改了RawBlock和RawInline的"格式"类型。如果将"html"和"tex"替换为(Format"html")和(Format"tex")，应该可以。 (假设除了编译器标记的问题之外，没有其他问题。)